Via Alberto Conti I re-discovered an animation from last year that shows the discovery of over 500,000 asteroids since 1980. The video shows the planets orbiting the Sun and each asteroid discovery is highlighted when it happens. As time runs into the 2000s the pace really picks up and the asteroid belt becomes incredibly obvious. You should quickly spot that the discoveries occur on the side of the Earth facing away from the Sun (i.e. when it's night) although there are some interesting evening/morning discovery wedges in 2010 and I'm not sure why.